A 3-dimensional nanobiosensor based on an anodic aluminum oxide template

In this paper, we propose a high sensitive nanobiosensor based on a 3D sensing element that has uniformly deposited gold nanoparticles. The sequential synthesis processes include: preparation of an AAO film; modification of the surface of its barrier-layer; deposition of a thin film of gold on the surface of the barrier layer; annealing; and electrochemical deposition of gold nanoparticles on the gold thin film; receptors or antibodies with respect to a certain biomarker were immobilized on the gold nanoparticles. The sensitivity of the proposed 3D gold-nanoparticle based nanobiosensor was verified using fluorescence analysis, cyclic voltammetry, and electrochemical impedance spectroscopy through the sensing experiments on biotin detection. The sensitivity of the biosensor can be markedly enhanced due to the following factors. (1)The 3D nanostructure of the AAO film increases the binding surface of the gold nanoparticles; (2)The symmetrical distribution of the electric field intensity during electrophoresis depositing results in an exceptionally uniform distribution of the gold nanoparticles; (3) Larger area of the sensing element further enlarges the sensing area.